Clean-room by design
Readable, original C++20 code and carefully documented evidence keep the new implementation separate from proprietary source code.
Work in Progress
An empire. A new beginning.
The first recomp project for Emperor: Rise of the Middle Kingdom.
An independent clean-room reimplementation in C++20 and SDL3. The growing sandbox brings roads, production, households and walkers to modern macOS and Linux systems, with widescreen support.
The project
Rebuilding a classic, cleanly.
OpenEmperor is written independently from documented behavior and original research. It does not distribute the original game, its data, or proprietary source code.
Your copy, your data
OpenEmperor reads files from your own legally obtained, installed or extracted copy of the original game. No original assets are bundled.
A modern foundation
SDL3, CMake, deterministic simulation, and bounded read-only asset tooling create a portable foundation for macOS and Linux.
Current development
A city taking shape.
The sandbox has grown beyond its first production chain. Homes, workshops and city services are connected by roads, with walkers moving through the settlement.
The sandbox in motion.
Quality of Life
A classic, with room to breathe.
Modern screens and modern systems make it easier to return to your city.
Widescreen support
More room for your settlement on modern, wide displays. Keep a wider view of your roads, buildings and walkers.
macOS & Linux
Run OpenEmperor on macOS and Linux, using your own original Emperor game data and a native C++20 and SDL3 foundation.
Published alpha · 0.1.0-alpha.1
Try the first playable release.
The public alpha provides an early sandbox for external testing: original-data setup, map loading, production, routing and OpenEmperor saves. The current development build shown above continues from that foundation.
Read the known issuesWhat the published alpha includes
- A main menu for selecting your own original game data and a supported standalone map
- The OpenEmperor Industry-v5 sandbox with roads, two clay sources, two potteries, one warehouse, four households, and five couriers
- Road placement and removal, production, supply, deterministic routing, and live rerouting
- OpenEmperor save and load support for the sandbox
- Optional local visual profiles for previewing walker, building, and road graphics supplied from your own game files
What it is not — yet
- A complete original-game experience or campaign recreation
- Compatible with original Emperor savegames
- A replacement for the original game data
- A notarized, production-ready macOS release
“Not a port. Not an asset pack. A new implementation, built from evidence and tested one system at a time.”
Before you begin
Bring the original. OpenEmperor brings the new foundation.
Use the packaged macOS alpha or build from source for Linux. Both need your own original game data.
macOS or Linux
The published download is an Apple Silicon macOS app. For Linux, build from the source repository.
Explore the sourceOriginal game data
You need a legally obtained, installed or extracted copy of Emperor: Rise of the Middle Kingdom. The GOG installer file itself is not a data folder.
Get Emperor on GOGAlpha expectations
The app is ad-hoc signed and not notarized. macOS may show a security warning, and incomplete visuals or diagnostic fallbacks are expected.
First run
Start your sandbox.
- 1Get OpenEmperor
Download the published macOS alpha or build the current source for Linux.
- 2Start the app
Open OpenEmperor.app on an Apple Silicon Mac, or run your compiled openemperor executable on Linux.
- 3Select your data
Choose the folder containing your installed or extracted Emperor game files, then start a supported sandbox map.
The road ahead
Built one verified layer at a time.
Development continues through small, testable systems: safer file interpretation, stronger visual compatibility, deeper authored sandbox rules, and a portable architecture. Each step keeps research evidence, original-game behavior, and OpenEmperor-authored mechanics clearly separated.
Questions
Before entering the sandbox.
Is OpenEmperor the original game?
No. It is an independent clean-room reimplementation and currently an experimental sandbox, not a complete recreation of Emperor: Rise of the Middle Kingdom.
Does the download include Emperor assets?
No. You must supply files from your own legally obtained, installed or extracted copy of the original game.
Which systems does OpenEmperor support?
macOS and Linux. The packaged 0.1.0-alpha.1 download is for macOS on Apple Silicon; Linux uses a source build.
Does OpenEmperor support widescreen displays?
Yes. The current development build supports widescreen displays so you can see more of your city.
Enter carefully
Help the city grow.
Try the experimental sandbox, read the known limitations, and report reproducible problems without uploading original game files.